selflessly, compassionately, not afraid. >> and president obama will be in boston thursday. they're having an enter faith service for -- interfaith service for the victims. our bruce leshan has been in boston and has the latest from there right now. >> reporter: we are just outside one of the law enforcement staging areas on the boston common. and the authorities are pledging to go to the ends of the earth to catch the killer or killers. but the fbi is also pleading for help closer to home. this special agent in charge says these killer or killers are somebody's neighbor, somebody's friend, somebody knows them. the person who did this is someone's friend, neighbor, coworker or relative. we're asking anyone who may have heard someone speak about the marathon or the date of april 15th in any way that indicated that he or she may target the event to call us. >> reporter: the fbi says the explosives were packed in two pressure cookers, stuffed in dark-colored bags and left on the ground. they were apparently loaded with nails and bb's designed to inflict maximum injury. the blas